package utils import "time" func StartOfDay() time.Time { ref := time.Now() return time.Date(ref.Year(), ref.Month(), ref.Day(), 0, 0, 0, 0, ref.Location()) } func StartOfWeek() time.Time { ref := time.Now() year, week := ref.ISOWeek() return firstDayOfISOWeek(year, week, ref.Location()) } func StartOfMonth() time.Time { ref := time.Now() return time.Date(ref.Year(), ref.Month(), 0, 0, 0, 0, 0, ref.Location()) } func StartOfYear() time.Time { ref := time.Now() return time.Date(ref.Year(), 0, 0, 0, 0, 0, 0, ref.Location()) } // https://stackoverflow.com/a/18632496 func firstDayOfISOWeek(year int, week int, timezone *time.Location) time.Time { date := time.Date(year, 0, 0, 0, 0, 0, 0, timezone) isoYear, isoWeek := date.ISOWeek() for date.Weekday() != time.Monday { // iterate back to Monday date = date.AddDate(0, 0, -1) isoYear, isoWeek = date.ISOWeek() } for isoYear < year { // iterate forward to the first day of the first week date = date.AddDate(0, 0, 1) isoYear, isoWeek = date.ISOWeek() } for isoWeek < week { // iterate forward to the first day of the given week date = date.AddDate(0, 0, 1) isoYear, isoWeek = date.ISOWeek() } return date }